Nepal's Langtang village from space: before and after

Wednesday, 13 May 2015 EARTH IMAGE by Stuart GaryABC

BEFORE: The Langtang region before the quake struck.(Source: NASA/LandSat8)

Earth image

AFTER: a mixture of snow, ice, and debris, which originated in snowfields on the slopes above Langtang, slid downhill completely covering the Langtang River and burying the village (Source: NASA/LandSat8)

The village of Langtang is gone, wiped of the face of the Earth by the first of the recent devastating Nepalese earthquakes.

The small village - shown in the BEFORE image - was located on a popular trekking route near the base of Mount Langtang.

On April 25 2015, it was buried under an avalanche of ice and rock, shaken loose by the massive 7.8 magnitude quake that struck the central Nepalese Himalayan Mountains northwest of the capital Kathmandu.

The AFTER image shows the path of the avalanche that slid downhill, covering the Langtang River and destroying the village. While cloudy conditions hampered satellite observations of Nepal in the days following the initial earthquake, the Operational Land Imager on LandSat 8 captured this view on April 30, 2015.

The initial earthquake, which lasted for about 100 seconds, was centred 15 kilometres below the village of Barpak in Gorkha district, about 75 kilometres northwest of Kathmandu.

The earthquake occurred when an area about 150 kilometres long and 50 kilometres wide in a fault running beneath the Kathmandu valley, gave way after decades of built-up pressure.

The rupture spread south eastwards for over a hundred kilometres.

The Indian plate is moving north at about two centimetres per year, and is constantly trying to subduct under the Tibetan plateau.

Data from another satellite called Sentinel-1A shows the boundary of the Indian and Eurasian tectonic plates experienced a vertical uplift of about a metre, and a north-south horizontal shift of up to three metres was also detected along the colossal fault line.

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